/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.flink.table.plan.rules.physical.stream

import org.apache.flink.table.api.TableException
import org.apache.flink.table.plan.nodes.FlinkConventions
import org.apache.flink.table.plan.nodes.logical.FlinkLogicalWatermarkAssigner
import org.apache.flink.table.plan.nodes.physical.stream.StreamExecWatermarkAssigner

import org.apache.calcite.plan.{RelOptRule, RelTraitSet}
import org.apache.calcite.rel.RelNode
import org.apache.calcite.rel.convert.ConverterRule

/**
  * Rule that converts [[FlinkLogicalWatermarkAssigner]] to [[StreamExecWatermarkAssigner]].
  */
class StreamExecWatermarkAssignerRule
  extends ConverterRule(
    classOf[FlinkLogicalWatermarkAssigner],
    FlinkConventions.LOGICAL,
    FlinkConventions.STREAM_PHYSICAL,
    "StreamExecWatermarkAssignerRule") {

  override def convert(rel: RelNode): RelNode = {
    val watermarkAssigner = rel.asInstanceOf[FlinkLogicalWatermarkAssigner]
    val convertInput = RelOptRule.convert(
      watermarkAssigner.getInput, FlinkConventions.STREAM_PHYSICAL)
    val traitSet: RelTraitSet = rel.getTraitSet.replace(FlinkConventions.STREAM_PHYSICAL)

    if (watermarkAssigner.rowtimeFieldIndex.isEmpty) {
      throw new TableException("rowtimeFieldIndex should not be empty")
    }

    if (watermarkAssigner.watermarkDelay.isEmpty) {
      throw new TableException("watermarkDelay should not be empty")
    }

    StreamExecWatermarkAssigner.createRowTimeWatermarkAssigner(
      watermarkAssigner.getCluster,
      traitSet,
      convertInput,
      watermarkAssigner.rowtimeFieldIndex.get,
      watermarkAssigner.watermarkDelay.get)
  }
}

object StreamExecWatermarkAssignerRule {
  val INSTANCE = new StreamExecWatermarkAssignerRule
}
